What evidence suggests that human ancestors walked upright before they evolved large brains?

Fossil evidence, such as Ardipithecus ramidus and Australopithecus afarensis, show adaptations for upright walking in their pelvis and lower limb bones. These early hominins also had a smaller brain capacity compared to later species like Homo erectus. By studying the fossil record and anatomical features, scientists have been able to reconstruct the gradual evolution of bipedalism preceding larger brain development in human ancestors.